It has become a trend among starting pitchers with one dominant pitch to throw it earlier in counts and to throw it more often. This defies conventional baseball wisdom, but several starting pitchers have found or recaptured success by featuring breaking balls more heavily.
Rich Hill, fighting for his baseball life, began using his curveball more and at different speeds in his late-30s to go from journeyman reliever to frontline starter. Chris Archer’s slider usage has gone up every season since his 2015 breakout, and his strikeout rate has climbed along with it. Patrick Corbin, who, despite injuries and control struggles, has always possessed one of the deadliest sliders in the game. Corbin has started throwing it 46% of the time in 2018 and has a 41% strikeout rate in his first two starts.
Two talented young Baltimore righties possess similarly nasty out-pitches compared to the aforementioned starters, yet have only seen success in small bursts. Dylan Bundy has been outstanding when he prominently features his slider. It has been the key his success early in the season. Bundy has thrown his slider 26.4% of the time thus far, and has a 1.35 ERA, 1.93 FIP, and 11.25 K/9 on the year. Kevin Gausman’s splitter rivals the effectiveness of Bundy’s slider, and he’s thrown it 23.64% of the time this season, but the results have been mixed thus far. Is there still the potential for Gausman to experience a breakout season?
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The Ballad of Dylan Bundy
Dylan Bundy was once the most prized pitching prospect in baseball. Tommy John surgery and shoulder injuries took away his elite velocity, but he still has a dominating slider. Those that follow Bundy or the Orioles more closely know that after four years between a major league pitch Baltimore had a moratorium on Bundy’s slider. He didn’t throw the pitch at all in 2016 while working primarily out of the bullpen, but it made a comeback in 2017. Bundy was amazing at times last season while using a slider heavy approach. Through three starts he has a 1.35 ERA and 32.5% strikeout rate. His slider has an unreal 37.55% whiff rate and batters have mustered just two singles for an .091 average against the pitch.
Bundy has used his slider about 26.4% of the time in his first three starts, which is higher than his 22.1% usage rate in 2017, but the season long usage does not tell the whole story. Those that owned Bundy last season know how volatile he was on a start to start basis. Even a cursory glance at his pitching lines will tell you that. In 2017 Bundy made 28 starts. In eight of them his ERA was over seven, and in 12 of them it was under three. What a lot of this volatility boiled down to was slider usage, and Bundy’s slider usage correlated with performance. Here’s a month-by-month chart demonstrating this.
Month | Slider % | FIP | K/BB |
April | 25.88% | 3.10 | 3.83 |
May | 16.77% | 5.06 | 1.86 |
June | 18.30% | 6.83 | 1.85 |
July | 17.99% | 6.31 | 3.17 |
August | 27.31% | 2.32 | 7.50 |
September | 29.66% | 4.88 | 2.50 |
Bundy’s September performance stands out, since he threw the slider the most, but also struggled. Could he have reached a breaking point? Perhaps, but Bundy made three starts in September before being shut down with a hamstring injury. He had a dazzling start against the Blue Jays that was sandwiched between two disasters. In one of them he only threw his slider 19% of the time and only got one whiff with it, and in the other he only gave up one extra base hit and was singled to death. That certainly exposes the risk on a start-by-start basis with a breaking ball heavy pitcher. If the pitcher doesn’t have a feel for the pitch or can’t command it on a given night, they don’t have anything to fall back on. Bundy’s fastball and changeup are fine complimentary pitches, but he isn’t the same guy if his slider isn’t working. There is a clear recipe for success here with Bundy and he is executing it this season with fantastic results.
Is Gausman Next?
Bundy’s teammate Kevin Gausman has his own devastating out pitch, and like Bundy Gausman has had bursts of success when using it. Gausman’s splitter has a 23.02% whiff rate and .199 average against over his career. What really makes the splitter an intriguing pitch is that it’s a split-changeup. When we think about splitters, we usually think split-fastball, but Gausman uses a splitter grip and throws the pitch about ten MPH slower than his fastball. The pitch has the same horizontal movement of his four-seamer and breaks downward. Here’s a clip of the pitch at its peak.
After a disastrous first half to 2017 Gausman posted a 3.41 ERA and 9.64 K/9 in the second half and that made him look like a breakout candidate going into 2018. Gausman’s success correlated with his splitter usage. Here is a month-by-month chart of splitter usage and performance.
Month | Splitter % | FIP | K/BB |
April | 14.58% | 6.22 | 1.18 |
May | 13.79% | 4.56 | 2.20 |
June | 20.31% | 4.81 | 1.79 |
July | 27.46% | 3.47 | 4.09 |
August | 22.87% | 5.35 | 2.25 |
September/October | 23.13% | 2.90 | 4.88 |
Gausman didn’t have his watershed moment until late-June. After three straight starts where he gave up at least four earned runs, Gausman began to use his splitter more and found the best success of his career. There were still some Gausman-esque hiccups, such as a four homer game in August that inflated his numbers, but there is a blueprint to success for him. So why doesn’t he just throw the splitter 25% of the time? Or more?
The biggest difference between Gausman’s splitter and Bundy’s slider, from a results perspective, is the power surrendered by each pitcher. Batters have a .131 ISO against Gausman’s splitter, where they only have a .068 ISO against Bundy’s slider. Home runs have long been an issue for Gausman, who is no stranger to the long ball. He owns a 1.28 career HR/9 and has given up four already this season. If the ball catches any of the plate it gets a one-way ticket to the moon. Here’s a ISO heapmap based on splitter location taken from brooksbaseball.net.
When his command is off Kevin Gausman turns into Kevin Gas-Can, a pitcher we’ve seen far too much over the last few years. Because of this home run issue his upside probably can’t reach Bundy’s level. Even though Bundy has a career 1.35 HR/9, his best pitch cannot be driven for power like Gausman’s splitter. Bad pitches and bad location hurt any pitcher on any pitch type, but Gausman does it far too often with an offspeed pitch and the results can be brutal.
Could Kevin Gausman just throw his splitter 25% of the time and deal with the home runs? Perhaps, and that may be the best thing for him considering the troubles he’s endured when relying more on his fastball and slider. It still makes him incredibly volatile on a start-by-start basis. Last season Gausman made 34 starts, and in 14 of them he gave up four or more runs. In 12 of them he gave up one run or less. We can’t exactly pick our spots with Gausman either. He put up stinkers against teams like the Pirates (28th in team wOBA last season), Angels (26th), and Royals (24th), and most of those starts came after his split-fingered epiphany.
Despite these flaws, there are some good signs from Gausman out of the gate. He has thrown his splitter 23.64% of the time, which would be new career high for him over an entire season. He also has a 12.7% swinging strike rate in his first three starts. In his worst start against the Twins he threw his splitter the least, and got tagged for three home runs. The splitter is as effective as ever. Batters are whiffing 27.69% of the time on the pitch, and hitting just .150 against it. What is concerning is Gausman’s velocity drop. Normally he sits around 95 MPH and touches 98, but so far he’s averaged around 92 MPH. He did sit at 94 MPH in his start against the Yankees on 04/06, but he has been around 92 MPH otherwise.
Gausman probably can’t make a Bundy-like transformation. Bundy has been more effective with his fastball and has a changeup to fall back on if he needs it. Gausman’s velocity drop has caused his four-seamer to get crushed during his first three starts, and his slider has always been a bad pitch that can’t be relied on for outs. That being said, on days where his splitter is working he can outright dominate lineups. There will starts, and perhaps even extended stretches where he looks like he’s turned a corner. There will also be starts where he doesn’t have it and gets shelled. It is the inherent risk given his arsenal, pitching style, and command. Still, better days are coming for Gausman, especially if his velocity returns as the weather heats up. He’s worth holding if you own him, and he’s a decent buy-low target if you want him, but the brilliance he shows will forever be transient.